Procedures for the detection of unwanted ingredients in Meat products with respard to BSE - 7. Detection of tissue of the brain with GC-MS

The detection of tissues of the central nervous system (CNS) is possible by means of gas chromatography and mass spectrometry using unusual so-called "CNS-specific" fatty acids as markers. In our own studies we further optimised the analytical procedure first described by NIEDERER and BOLLHALDER (2001) as pertaining to extraction (mean increase: 2.5) and instrumental analysis (mean increase: 10). All of the fatty acids we tested were found in the CNS in very high contents; however, traces were also detectable in CNS-free standard material and in pure muscle tissue. Cerebronic acid (C24OH) was found to be the marker best suited for the correct detection of bovine CNS in meat products down to a limit of 0.2 % (cutoff value, 99.9 % statistical security). Using the differences of the contents of "CNS-specific fatty acids and their relationships (especially cis-/trans-nervonic acid) we identified in a blindfold experiment the CNS of bovine, porcine, ovine and avian origin in standards of emulsion type sausages. Moreover, the correct classification of the age of the CNS was lab internally possible in porcine and bovine CNS. Further intensive studies are needed to further characterize variance and specificity. However, it would already be possible for official food control using this GC-MS procedure to correctly identify adult bovine brain as specified risk material (SRM) according to directive (EC) 999/2001 in meat products